Gas meter with unitary central core defining multiple flow passages

ABSTRACT

A dry gas meter includes a unitary core which functions as the meter casing and defines the inner sides of two gas chambers, a valve gear chamber, an index housing and multiple gasways. A central partition of the core has angled wall portions which provide dished sides for the gas chambers. The gas chambers are further defined by diaphragm carrying pan covers. These pan covers and upper and lower covers complete the body of the meter. Between the angled wall portions, gasways extend from a gas inlet formed in the lower cover to the interior of a valve gear chamber.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a dry gas meter of the kind in which flexiblediaphragms work back-and-forth in chambers to which the gas beingmetered is alternately admitted and exhausted. Such meters will betermed hereinafter "meters of the kind described".

2. Discussion of the Prior Act

Conventionally meters have had their working parts located in anexternal casing. For example DE-A-1473042 shows upper and lower externalcasing parts secured together by flanges adjacent the midheight of themeter and enclosing all the meter parts. Similarly DE-A-2756163 showsmeter parts which are intended to be included in an external casing.DE-C-733288 shows a simple meter which may have no external casing butdoes not have a unitary core defining first, second and third chambersin accordance with those of the present invention.

FR-A-1466742, which is regarded as the closest prior art, comprises aunitary core defining first, second and third chambers. However, it isnot clear that this meter is not intended to have an outer casing andthere is no fourth lower chamber and lower cover member.

It is desired that meters of the kind described be made smaller, neaterand of simpler construction without loss of strength of durability.

SUMMARY OF THE INVENTION

The invention provides a meter of the kind in which flexible diaphragmswork back-and-forth in first and second chambers to which the gas beingmetered is alternately admitted and exhausted by valve means, theoscillations of the diaphragms being translated through an index drivemeans for counting to give an indication of the volume of gas which haspassed through the meter, the meter being formed by a core providing inone piece the structure for the inner halves of the first and secondchambers and also providing a third upper chamber for the valve meansand the index drive means; first gasways connecting the first and secondchambers to the third chamber; an upper cover for closing the thirdchamber and defining an outlet means; two separate pan covers attachedto the core to complete the first and second chambers; by second gaswaysdefined by the core and extending from adjacent the bottom of the coreto the third chamber for connecting a gas inlet means at the bottom ofthe meter to said third chamber; and wherein the upper cover and a lowercover form the top and bottom respectively of the meter casing with thecore and pan covers forming the outer sides of the meter casing, therebeing no further external casing.

Such a meter can be made small and provides for the quick and easyassembly of the meter, wherein the operation of attaching the pan coverscompletes the gasway connections to the pans which are otherwiseintegral in the core. Since no outer casing is needed, the time anddifficulty of the assembly is very much reduced.

BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENT

A specific embodiment of the invention is shown in the accompanyingdrawings, in which:

FIG. 1 is an exploded perspective view of the main components of a gasmeter,

FIG. 2 is an exploded perspective view of the upper part of the meter ofFIG. 1,

FIG. 3 is a vertical section through a central unitary part of the meterof FIG. 1,

FIG. 4 is a horizontal section on the line IV--IV of FIG. 3,

FIG. 5 is a vertical section on the line V--V of FIG. 3, and

FIG. 6 is an exploded perspective view from the upper end of the gasmeter of FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The gas meter comprises two chambers (11, 12) each divided vertically bya flexible diaphragm (13) so that gas being measured may be alternatelyadmitted and exhausted from either side of the diaphragm, causing it tooscillate back-and-forth. As is usual, the oscillations of the diaphragmare counted to provide a measure of the volume of gas which has passedthrough the meter.

As seen best in FIG. 1, the meter body is defined by a unitary core (15)which is a complex aluminium die casting providing structure functioningas the meter casing, inner gas chamber, valve gear container, indexhousing and gasways, as described hereinafter in more detail. The corecomprises a central vertical partition (16) comprising one side of eachof the chambers (11, 12), and two angled walls (17) on either side ofthe partition each forming one dished shape of a chamber. The upper endof the core forms a recess (19) opening to the side which is the indexhousing, and an irregular housing (23), [FIGS. 3 and 5] opening to thetop which houses valves, valve drive gear, and index drive means.

The lower end of the core forms a housing (20) across the coreconnecting at each side with vertically-extending, triangular-sectiongas inlet gasways (21, 22), seen best in FIGS. 3 and 4. These gaswayslie in between the angled walls (17) using space which would otherwisebe wasted.

The two chambers are completed by cast aluminium outer pans (25, 26)[FIG. 1], each having a flexible diaphragm (13), and both secured to thecore (15). Each diaphragm has a central disc (27) secured by a flag amto a flag (28) [FIG. 6 ] extending into housing (23) to drive the valvedrive gear and index drive means.

The lower housing (20) is closed by a cast aluminium lower cover (30)[FIG. 1 ] having a central bossed gas inlet (31) which communicates withhousing (20) and gasways (21, 22). The upper housing (23) is closed by acast aluminium upper cover (33) having a central bossed gas outlet (34)which communicates with an exhaust tube (36) [FIG. 6] in housing (23).

The index housing (19), as best seen in FIG. 2, houses an index assembly(34) and has a cover (35) having a viewing plate through which the meterreading can be read. A sealed bush bearing (37) in the rear wall of thehousing allows a lay shaft (41) [seen also in FIG. 6] passage to drivean output gear (38) and through it change gear (39) and index drive gear(40), which operates the index assembly (34) to count the oscillationsof the diaphragms.

Adjacent each outer pan (25, 26), the core (15) has an angled face (43,44) [FIG. 1], which mates with a similarly angled face (45, 46) on thecorresponding outer pan. Gasways (47, 48) in the core connect with ports(50) in the faces (45, 46) into the interior of the pans on the outerside of diaphragms (13).

On the inner side of the diaphragms (13) the core provides gasways (51),also connected to the interior of the chambers (11, 12).

Gasways (51, 48, 47) all extend up through the core and through a lowerwall of upper housing (23) ending in the same plane as seen best in FIG.3. Exhaust tube (36) [FIG. 6] is forked to provide a pair of entrances(61) and the tube is mounted so that these lie in the same plane as theentries to gasways (51, 48, 47). A valve grating (60) [FIG. 6 ] for eachchamber (11, 12) covers the two gasways to either side of the diaphragmand one of the exhaust tube entrances (61). Inlet gasways (21) and (22)open into the upper housing (23) so that it is at all times filled withthe gas being metered. An oscillating valve cover (62) for each valvegrating alternately admits gas from housing (23) to either side of thediaphragm and exhausts it from the chambers into exhaust tube (36) andout of outlet (34'). Thus the flowing gas is forced to move thediaphragms back-and-forth and oscillate flags (28). Flags (28) drive toparms (64) which are connected to cranks (65) to rotate a gear box (66).Gear (67) driven by the gearbox connects with output gear (68) whichrotates layshaft (41) which, as discussed above, drives the index.

Cover drive arms (69) are driven from gears (70) of the gearbox andconnected to the valve covers (62) to oscillate them as described above.

It will be noted that the meter design is distinguished by aparticularly efficient use of space so that the overall size is kept toa minimum. The two pan covers (25) and (26) fit neatly against the core,their outer surfaces being flush with the outer surfaces of the upperpart of the core. Moreover, the spaces between the outer edges of thechambers, which are usually wasted, have been used here to provide inletgasways (20, 21, 22) which thus do not add to the overall size of themeter. This is most conveniently effected by the core being a diecasting allowing all the passageways to be preformed without extra pathsor assembly work.

Since the pan covers, the top cover and the lower cover are all rigidaluminium castings, the core and its covers are all of strong anddurable enough construction to need no outer casing for protection, thisalso contributing in major part to the reduced size of the meter.

The assembly of the meter is also very much simplified by the use of theunitary core. In assembly, the pan covers and diaphragm and flagstructures are separately put together and then secured to the core. Thelower cover is secured in position, thus completing all the gaswayconnections. The valves and drive gear are assembled in housing (23) andthe upper cover secured over the top. The index is then assembled andattached into the index housing. No casing operations as such arerequired, the unitary core, pan covers and upper and lower coverstogether forming the outer surfaces of the meter.

I claim:
 1. A gas meter comprising:a unitary central core includingfirst and second end portions, said core defining first portions offirst and second chambers between said first and second end portions,and a third chamber located at said second end portion; a first pancover attached to said core and defining a second portion of said firstchamber; a second pan cover attached to said core and defining a secondportion of said second chamber; first and second flexible diaphragmsmovably mounted in said first and second chambers respectively; aplurality of first gasways respectively interconnecting said first andsecond chambers with said third chamber, at least a portion of each ofsaid plurality of first gasways being formed as part of said core; valvemeans, located in said third chamber, for alternately admitting andexhausting a gas on opposing sides of said diaphragms to cause saiddiaphragms to oscillate; index drive means interconnected with saiddiaphragms such that oscillations of said diaphragms shift said indexdrive means to provide an indication of the volume of gas passingthrough said meter, said index drive means being located, at least inpart, in said third chamber; a first cover secured at and closing thefirst end portion of said core; a gas inlet provided at the first endportion of said core; second gasways extending from said first endportion to said third chamber thereby connecting said gas inlet to saidthird chamber, said second gasways being defined by said core; a gasoutlet opening into the third chamber; and a second cover secured at thesecond end portion of said core and closing said third chamber, whereinouter portions of said core, said first and second pan covers and saidfirst and second covers define outer sides of said gas meter.
 2. The gasmeter as claimed in claim 1, wherein each of said first and second pancovers includes a port connected with a respective one of said firstgasways.
 3. The gas meter as claimed in claim 1, wherein said gas inletis formed in said first cover, said core further defining a fourthchamber communicating with said gas inlet and said second gasways. 4.The gas meter as claimed in claim 3, wherein said core further comprisesa central partition forming one side of each of the first and secondchambers, said central partition including angled walls, said secondgasways opening at said angled walls.
 5. The gas meter as claimed inclaim 1, wherein said core further comprises an index chamber, saidindex drive means being located, at least in part, in said indexchamber, said gas meter further comprising a viewing plate extendingover said index chamber.
 6. The gas meter as claimed in claim 1, whereinsaid gas outlet is formed in said second cover and communicates with aforked exhaust tube located in said third chamber, said forked exhausttube defining a pair of entrances associated with said valve means. 7.The gas meter as claimed in claim 1, wherein said core is die casted ofaluminum.
 8. The gas meter as claimed in claim 1, wherein said first andsecond diaphragms are carried by said first and second pan coversrespectively.